CN100403975C - Finger-worn medical sensors - Google Patents

Abstract

The present invention relates to a medical sensor (1) for measuring pulse, blood, tissue and/or skin parameters using electromagnetic waves in the transmission method, comprising a carrier part (2) for pushing onto a patient's finger or toe. A first carrier leg (12) carries a transmitter unit (5) and a second carrier leg (13) carries a receiver unit (6). A carrier base (14) connects the two carrier legs (12, 13) to one another in the region of a tip of the finger or toe. A spring part (3) is arranged on the outside of the carrier part (2) such that a first spring leg (15) bears against the first carrier leg (12) and a second spring leg (16) bears against the second carrier leg (13). The carrier part (2) is made of a more flexible material than the spring part (3), in which the spring legs (15, 16) prestress the carrier legs (12, 13) toward one another.

Description

Finger-worn medical sensors

The invention relates to a medical sensor for measuring pulse, blood, tissue and/or skin parameters using electromagnetic waves in a transmission method.

During operations or intensive care, inter alia, the patient's lung function, metabolism and heart rate need to be checked and monitored. This can be done, for example, by measuring oxygen saturation and pulse rate. For this purpose, sensors of the above-mentioned type can be used and used to carry out pulse-derived arterial oxygen saturation measurements by means of photoemission measurements. Such sensors generally comprise at least one emitter, such as a light-emitting diode or LED emitting infrared light and an LED emitting red light, and at least one receiver, usually a photodiode, as well as a carrier assembly, which integrates the sensor in the desired manner. The transmitter and receiver are placed on the patient's finger or toe.

With regard to these sensors, a distinction is made between disposable sensors, partially reusable sensors and reusable sensors.

Among patients of different body sizes, the diameters of fingers and toes differed significantly. Therefore, patients are grouped according to their body size, eg large adult, adult, small adult and child.

A sensor designed as an adhesive sensor is known from EP 0127947 B1, wherein the carrier part basically comprises an adhesive tape that is wrapped around the finger or toe and adhered thereto. Although such adhesive sensors are designed as disposable sensors, they are relatively expensive due to their complicated manufacture. In order to obtain correct measurement results, the adhesive sensor must be carefully positioned according to the size of the corresponding finger and/or toe. In order to simplify or enable the attachment of the adhesive sensor to different sized patients, the adhesive sensor usually has different sizes.

In US Pat. No. 3,810,460 and US 4,685,464, sensors designed as clip-on sensors are disclosed, which in each case have two feet mounted relative to each other so that they can pivot around a pivot. One of the legs contains the transmitter, while the other leg contains the receiver. In known clip-on sensors, the emitting direction of the transmitter and the receiving direction of the receiver vary as a function of the deflection angle between the legs of the clip. Consequently, the known clip-on sensor can only provide reliable measurement results within a predetermined narrow angular range. Thus, clip-on sensors must be provided in different sizes for patients of different body sizes. Also, at larger opening widths, the pressure on the fingers or toes created by clamping the feet is great enough to impede the blood supply and erroneous measurements. Clip-on sensors are constructed in a relatively complicated manner, so they can only be used as reusable sensors.

Other sensors designed as telescopic sensors are known from DE 3703458 C2 and US 4109643. In the case of a sleeve sensor, the carrier part is designed as a sleeve which can be pushed onto the finger or toe and then wraps around the finger or toe. However, the opening width of the sleeve can only be varied to a relatively limited extent. For larger fingers or toes, the pressure becomes great enough that blood flow in the finger or toe is obstructed. For smaller fingers or toes, contact with the surface may be lost, so measurements are also not possible in this case. Furthermore, these sleeve sensors are constructed in a relatively complicated manner, so that they are relatively expensive to produce and can only be used as reusable sensors.

A common feature of known sensors is that they are only suitable as reusable sensors due to their complex design and/or in order to achieve a sufficiently high functional reliability they have to be provided in different sizes so that they can be used on different bodies. Perform the required measurements on the sized patient.

The object of the present invention is to specify an improved embodiment of a medical sensor of the type mentioned in the introduction which, inter alia, allows the necessary measurements to be performed on many, preferably all conventional patients with one size sensor. In addition, it should be possible to manufacture the sensor in an economical way that can be provided as a disposable sensor.

According to the object of the present invention, there is provided a medical sensor for measuring pulse, blood, tissue and/or skin parameters using electromagnetic waves in a transmissive method, -comprising a clip-shaped carrier intended to be pushed on a patient's finger or toe part,

- wherein the first carrier foot of the carrier part carries at least one emitting element and rests on the finger or toe with the inner side of the first carrier foot during the measuring operation,

- the second carrier foot of the carrier part carries at least one receiving element and rests on the finger or toe during the measuring operation with the inner side of the second carrier foot opposite the first carrier foot,

- the carrier base of the carrier part interconnects the first and second carrier feet in the region of the fingertips or toes,

- providing a clip-like elastic portion having first and second elastic legs and an elastic base connecting said first and second elastic legs,

- the elastic part is arranged on the outer side of the carrier part, so that the first elastic foot rests on the outer side of the first carrier foot and the second elastic foot rests on the second carrier on the outside of the foot,

- said carrier part is made of a more flexible material than said elastic part,

- said first and second elastic feet prestress said first and second carrier feet towards each other.

The invention is based on the general concept of equipping the sensor with a clip-like flexible carrier part and a clip-like but stiffer elastic part, wherein the more flexible carrier part carries the transmitter and receiver on opposite carrier legs , while the harder elastic portion prestresses the carrier legs towards each other via the opposing elastic legs. With the proposed design, the functions "holding and positioning the transmitter and receiver" and "fixing the sensor on the finger or toe" differ from each other and are assigned to different components. As a result, various components can be optimized in terms of their functionality. According to the invention, the carrier part is designed to be more flexible than the elastic part, with the result that the carrier part is in each case better adapted to the inserted finger or toe. In contrast, the elastic part generates the necessary fastening force by elastic force in order to hold the sensor on the corresponding inserted finger or toe.

The sensor according to the invention works in principle similar to a clip-on sensor, but does not require a positioning shaft and can therefore be produced in a relatively economical manner. By configuring the carrier part and the elastic part in each case with two feet connected to each other by a base, the sensor can be dimensioned in a comparatively simple manner such that it can be used for larger finger or toe diameter ranges.

A particularly economical production is possible when the carrier part is produced in one piece and/or when the elastic part is produced in one piece. The carrier part and/or the spring part can then be produced economically in large quantities, with the result that the production costs of the sensor are significantly reduced.

In one embodiment, the elastic part has at least one elastic region which connects two support segments adjacent to it, said support segments being stiffer than the elastic region, which is particularly advantageous. With this design, the elastic characteristics of the elastic portion can be intentionally arranged such that there is a restoring force adapted to the width of the opening.

When the elastic part has two or more elastic regions, it is advantageous if these elastic regions are arranged to have different stiffnesses. This measure also simplifies the adaptation of the elastic characteristics of the sensor to the requirements of different finger or toe diameters.

In one embodiment, the support segment adjoining the more flexible elastic zone forms a stop portion which limits bending deformation in the elastic zone to a predetermined extent during expansion of the carrier legs, such an embodiment in particular Having attention. Thanks to this design, a step in which the stiffness of the elastic part changes in a step-wise manner is achieved by impeding the elastic characteristics of the sensor. Thanks to this design, the adaptation of the restoring force to the requirements of fingers or toes of different sizes can be improved.

Another important embodiment is characterized in that on the outside of the carrier part there is a groove extending from the outside of the first carrier foot via the outside of the carrier base to the outside of the second carrier foot, in which at least one emitting element and at least one A receiving element, and in it the connection cables for the transmitting element and the receiving element are placed, wherein the elastic part closes the groove from the outside. In this design, the optoelectronic components and their cables can be accommodated in the carrier part in a relatively simple manner. The secure fixing on the carrier part is then ensured by the associated elastic part, as a result of which the elastic part is given an additional function. Assembly of the sensor is thus simplified.

Other important features and advantages of the invention appear in the dependent claims, the drawings and the associated description of the drawings with reference to the drawings.

It is understood that the features mentioned above and below can be used not only in the combination as stated in each case but also in other combinations or alone without departing from the scope of the present invention.

The invention will now be further described with reference to an example of embodiment as shown in the drawings, but to which the invention is not limited. In the drawings, the same reference numerals denote the same or functionally identical or similar components.

Figure 1 shows a perspective view of individual components of a sensor according to the invention.

FIG. 2 shows a longitudinal section through the carrier part of the sensor along section line II shown in FIG. 3 .

Figure 3 shows a front view of the carrier part.

Figure 4 shows a rear view of the carrier section.

Figure 5 shows a top view of the carrier part.

Figure 6 shows a bottom view of the carrier part.

Figure 7 shows a longitudinal section similar to Figure 2 but through the elastic part of the sensor.

As shown in FIG. 1 , a medical sensor 1 according to the present invention includes a carrier part 2 , an elastic part 3 and a signal transmission unit 4 . Additionally, securing bars or straps 48 may be provided. The sensor 1 is used to measure pulse, blood, tissue and/or skin parameters on the patient's finger or toe. The sensor 1 can additionally be used to measure the oxygen saturation and at the same time to determine the pulse rate. The sensor 1 operates with electromagnetic waves, preferably visible and/or invisible light. The sensor 1 works according to the transmission principle, wherein electromagnetic waves from at least one transmitting element impinge on the finger or toe, and the waves emerging from the other side of the finger or toe are measured and evaluated by at least one receiving element.

To this end, the signal transmission unit 4 comprises a transmitter unit 5 comprising at least one transmitting element which will not be described in further detail here. Such emitting elements can be formed, for example, by LEDs. The signal transmission unit 4 also comprises a receiver unit 6 comprising at least one receiving element which will not be detailed further here. Such a receiving element can be, for example, a photodiode. The transmitter unit 5 or its transmitting element and the receiver unit 6 or its receiving element are connected to the plug 9 of the signal transmission unit 4 via a first cable 7 and a second cable 8 respectively. In this case, the separate second cables 8 of the receiver unit 6 are combined to form a hub cable 10 . The hub cable 10 and the individual first cables 7 of the transmitter units 5 combine to form a common cable 11 leading to the plug 9 .

The carrier part 2 is designed in the manner of a clip and thus has two carrier feet arranged opposite one another, namely a first carrier foot 12 and a second carrier foot 13 . In FIG. 1 the two carrier feet 12 , 13 are connected to each other on the side facing away from the viewer via a carrier base 14 . In the preferred embodiment shown here, the carrier part 2 is produced in one piece. The carrier part 2 is made of a softer elastically deformable material. The shape of the carrier part 2 or its carrier feet 12, 13 is selected such that the carrier part 2 can be pushed onto the patient's fingers or toes from the front. The carrier base 14 thus lies in the region of the fingertip or toe tip during the measuring operation.

The elastic part 3 has approximately the same contour as the carrier part 2 . In particular, the elastic part 3 is similarly designed in the manner of a clip and thus has two elastic feet, namely a first elastic foot 15 and a second elastic foot 16 . The elastic feet 15 , 16 are also connected to each other on one side by means of an elastic base 17 . The elastic part 3 is preferably also produced in one piece, but from a harder elastically deformable material. The terms "softer" and "harder" refer to the relationship between the carrier part 2 and the elastic part 3 .

As shown in FIGS. 2 to 6 , the carrier legs 12 , 13 are in each case bent inwards toward one another on mutually facing inner sides 18 , 19 . The respective carrier foot 12 thus has two laterally outwardly arranged side cheeks 20 and 21 which in each case protrude from the central region 22 or 23 towards the respective opposite carrier foot 12 , 13 . It can be seen from FIG. 3 that the side cheeks 20 of the first carrier foot 12 and the side cheeks 21 of the second carrier foot 13 are aligned with each other such that the carrier feet 12, 13 are in the position in which they are pressed together to the greatest extent. In the initial state they contact each other at their side cheeks 20 , 21 .

The carrier part 2 on the outer side comprises a groove 24 which extends from the outer side 25 of the first carrier foot 12 via the outer side 26 of the carrier base 14 to the outer side 27 of the second carrier foot 13 . In the first carrier foot 12 the recess 24 forms a first recess 28 for receiving the transmitter unit 5 . In the second carrier foot 13 the groove 24 forms a second recess 29 for receiving the receiver unit 6 . Between these two recesses 28, 29, the groove 24 forms a cable channel 30 in which the second cable 8 or the hub cable 10 can be placed. The first carrier foot 12 contains a further cable channel 31 , which leads from the front side of the first carrier foot 12 facing away from the carrier base 14 into the recess 28 . An end section 32 of a utility cable 11 can be placed in this further cable channel 31 (see FIG. 1 ). The first recess 28 includes a transmitting hole 33 through which at least one transmitting element can transmit electromagnetic waves to the receiver unit 6 . The second recess 29 accordingly contains a receiving opening 34 through which at least one receiving element can receive the waves emitted by the transmitter unit 5 .

To assemble the sensor 1 , the end section 32 of the common cable 11 is introduced into the further cable channel 21 and suitably fixed therein, for example by clamping or gluing. The transmitter unit 5 is inserted into the first recess 28 and suitably fixed therein by eg gluing. In addition, the receiver unit 6 is inserted into the second recess 29 and suitably fixed therein by, for example, adhesive. The hub cable 11 is placed in the cable channel 30 . The elastic part 3 is then placed on the outer side of the carrier part 2 . The elastic portion 3 serves as a cover or cover for the groove 24 . This means that the assembled elastic part 3 covers or closes the recesses 28 , 29 and the cable channels 30 , 31 . The elastic part 3 is also conveniently fixed on the carrier part 2 by suitable means such as welding. The carrier part 2 has on the outside a receiving contour 35 adapted to the contour of the elastic part 3 . Thus, the elastic part 3 is sunk at least partially into the outer side of the carrier part 2 and is secured laterally by the receiving contour 35 .

The elastic part 3 connected to the carrier part 2 is indicated by dashed lines in FIGS. 2 to 6 .

As shown in FIG. 7 , the clip-like elastic portion 3 is also conveniently manufactured in a single piece. In this case, the elastic part 3 is made of a material that is elastically deformable, in particular elastically springable, but stiffer than the material of the carrier part 2 . The elastic part 3 is thus made of a harder material than the carrier part 2 .

The elastic part 3 has at least one elastic zone, here two elastic zones, namely a first elastic zone 36 and a second elastic zone 37 . Each elastic zone 36 and 37 connects together two support sections 39 in the elastic part 3 which adjoin the elastic zone. Specifically, the first elastic region 36 connects the first support segment 39a with the second support segment 39b, and the second elastic region 37 connects the second support segment 39b with the third support segment 39c. The configuration of the elastic regions 36 , 37 is chosen such that the elastic regions 36 , 37 are in each case more flexible than the adjacent support section 39 . This means that the support section 39 has a higher stiffness than the elastic regions 36 , 37 arranged between them.

In the preferred embodiment shown here, the first elastic zone 36 is formed at the transition portion 40 between the second elastic foot 16 and the elastic base 17 . Here, the first elastic region 36 is formed by reducing the material, and as a result, the first elastic region 36 has a lower elasticity.

Here, the second elastic region 37 is formed substantially in the middle of the elastic base 17 . The second elastic region 37 is realized by a straight section 44 which reduces the wall thickness of the elastic base 17 in the region of the second elastic region 37 . The second elastic region 37 is configured such that its stiffness is greater than that of the first elastic region 36 .

The first elastic foot 15 here comprises two sections, namely an end section 42 and a starting section 43 . The start section 43 directly adjoins the elastic base 17 , whereas the end section 42 is remote from the elastic base 17 . The two segments 42 , 43 differ from each other, with the end segment 42 being more flexible than the starting segment 43 . Here, this is achieved through different material thicknesses. It can be seen from FIG. 7 that the end section 42 adjoins the start section 43 in the region 38 . This area 38 is arranged along the first elastic foot 15 such that it is arranged approximately centrally with respect to the second elastic foot 16 . Typically, this area 38 is then positioned in a position where the end of the fingernail or toenail would be located away from the tip of the finger or toe of the finger or toe inserted into the sensor 1 . In this case, the transition between the two segments 42 , 43 is formed by a step 41 in the region 38 . The elasticity of the end section 42 is conveniently adapted to the elasticity of the first elastic region 36 and the second elastic region 37 . The end section 42 may conveniently be provided with a higher stiffness than the second elastic zone 37 . The two elastic regions 36, 37 and the relatively flexible end section 42 form three preferred bending regions in the elastic part 3 which are more flexible during the expansion of the elastic legs 15, 16 than the adjoining support section 39a. , 39b, 39c are more elastically deformed.

The sensor 1 according to the invention operates as follows:

In the starting position, that is to say before the sensor 1 is pushed onto the finger or toe, the elastic part 3 places the sensor 1 or the carrier part 2 in the starting position. In the assembled sensor 1 , the spring legs 15 , 16 bear against the outer sides 25 and 27 of the carrier legs 12 , 13 and press them in opposite directions. The elastic part 3 is designed in such a way that it brings the carrier feet 12 , 13 against each other at their side cheeks 20 , 21 in the initial state. The sensor 1 is conveniently dimensioned such that it can be pushed on a child's finger or toe by lifting the two carrier feet 12, 13 away from each other. It can thus be ensured that the required application force for bringing the carrier feet 12 , 13 against the finger or toe can be achieved even for little fingers or toes. When the carrier legs 12, 13 are opened, the first elastic zone 36 begins to deform to a maximum extent. The resulting resilience is relatively small. Thus, even in children, who typically have lower blood pressure than adults, this restoring force does not lead to any damaging effects on blood flow and pulse. Instead, the restoring force creates sufficient pressure to secure the sensor 1 sufficiently on the finger or toe.

When the sensor 1 is attached to a larger child or a smaller adult, the second carrier leg 13 can pivot outwards to a sufficiently wide extent, and the restoring force increases the elastic characteristics of the elastic part 3 accordingly.

For an adult of average stature, the bending deformation of the first bending zone 36 reaches a predetermined value during the expansion of the carrier legs 12, 13, which is determined by the specific embodiment of the elastic part 3 shown in FIG. The blocking portion 45 is defined or defined. The stop portion 45 is formed by the sides of the supporting sections 39a, 39b adjacent to the first elastic zone 36, which abut against each other when a predetermined bending deformation is reached, thus preventing the first elastic zone 36 from breaking. Further bending deformation. With this special design, the elastic characteristic of the elastic part 3 presents a step at this point. This is because below this bending deformation limit there is approximately a continuous connection of the stiffnesses of the three bending zones 36, 37, 42, whereas beyond said bending deformation there is only the second elastic zone 37 and the end section 42 continuous joints of stiffness. This means that during bending of the carrier legs 12 , 13 , the restoring force increases to a lesser extent until a predetermined bending deformation is reached than with a more violent opening of the carrier legs 12 , 13 . This more drastic opening is achieved when the sensor 1 is used on an average adult or a larger adult. In these cases, greater restoring forces are also required in order to be able to obtain correct measurement results.

For larger adults, the bending deformation in the second elastic zone 37 can also reach a limit value, wherein the elastic characteristics of the second elastic zone 37 can be significantly increased by design. A further expansion of the carrier legs 12 , 13 thus acts approximately on the end section 42 . This means that the elastic characteristic of the elastic part 3 also exhibits a second step in which the stiffness of the elastic part 3 changes again.

Due to the shape of the carrier part 2, there are only relatively slight changes in the alignment of the transmitter unit 5 relative to the receiver unit 6 during bending of the carrier legs 12, 13, so that for very large opening width ranges As far as the carrier feet 12 , 13 are concerned, sufficient functional reliability for the measurements to be performed can be ensured.

Due to the clip-like configuration of the carrier part 2 , the carrier feet 12 , 13 lie flat on the upper and lower sides of the respective finger or toe and face each other on their inner sides 18 , 19 . The side cheeks 20 , 21 result in a central arrangement of the fingers or toes, with the result that the sensor 1 has an increased lateral holding force. Between the carrier feet 12, 13, the sensor 1 is open at the sides, thereby alleviating the accumulation of sweat on the fingers or toes. The shape of the carrier part 2 is also chosen such that the insertion depth of a finger or toe is limited. This can be achieved in that the second carrier foot 13 forms an upward ramp 46 where it adjoins the carrier base 14, against which the tip of a finger or toe rests when the optimum insertion depth is reached. on this slope. In the preferred embodiment shown here, the carrier base 14 is configured in longitudinal section with a U-shape as shown in FIG. 2 , with the result that the carrier base 14 forms a concave section 47 . In patients with longer fingernails or toenails, if the fingernail or toenail protrudes beyond the tip of the finger or toe, the concave section 47 can be used to accommodate the corresponding fingernail or toenail. Therefore, measurements are not disrupted by relatively long fingernails or toenails.

As soon as the sensor 1 has been pushed onto the patient's finger or toe, the sensor 1 is in principle sufficiently fixed on the finger or toe by the restoring force of the elastic part 3 in order to be able to carry out corresponding measurements in a correct manner. In order to avoid changes in the position of the sensor 1 relative to the finger or toe due to voluntary or involuntary movements of the patient, additional fastening means for fixing the sensor 1 to the finger or toe can be provided. For example, for this purpose, it is possible to use a fastening strap 48 as shown in FIG. The sensor 1 is thereby enclosed. In a more comfortable solution, fastening means can be provided on the carrier part 2, which fasten the sensor 1 better on the finger or toe. As an example, such a fastening device can be configured as a latch or clip closure, which can fasten the carrier legs 12 , 13 to one another at the respective opening width. It is likewise possible to attach to one of the carrier feet 12 , 13 a Velcro closure which wraps around the finger or toe after the sensor 1 has been pushed on.

Due to the simple design of the sensor 1 according to the invention, the sensor can be configured as a disposable sensor, for example. Suitable materials for the carrier part 2 are therefore relatively cheap polymers such as crayton or TPE (polyolefin thermoplastic rubber). Suitable materials for the elastic portion may thus be relatively inexpensive polymers such as polystyrene, ABS or SAN. The optoelectronic components, ie the transmitter unit 5, the receiver unit 6 and the plug 9, can also be made of less expensive components.

Alternatively, the sensor 1 according to the invention can also be designed as a reusable multiplex sensor. For the manufacture of the carrier part 2 high-quality polymers such as silicone or polyurethane are suitable. The elastic part 3 can likewise be made of a high quality polymer such as polyoxymethylene or polyamide. Photovoltaic components are also available using high-quality components suitable for a variety of applications.

In summary, the invention is characterized in that the sensor 1 comprises a relatively flexible carrier part 2 for fixing the transmitter unit 5 and the receiver unit 6, and is arranged on the outside of the carrier part 2 and presses the carrier part 2 against the fingers or toes. A relatively rigid elastic part 3 for measurement purposes. The U-shaped or C-shaped or clip-shaped configuration of the carrier part 2 and elastic part 3 allows the sensor 1 to be used on fingers or toes of various sizes, so that the same sensor 1 can be used consistently in different patient populations. As a result, it is possible to increase the number of sensors manufactured and thereby reduce their price. The elastic part 3 can be designed with low complexity, so that the sensor 1 has elastic characteristics that always produce a suitable applied force for fingers or toes of different sizes.

label list

1 sensor

2 Carrier part

3 Elastic part

4 Signal transmission unit

5 transmitter unit

6 receiver unit

7 first cable

8 second cable

9 plugs

10 hub cables

11 public cable

12 first carrier foot

13 Second carrier feet

14 carrier base

15 The first elastic foot

16 Second elastic leg

17 elastic base

18 The inner side of the first carrier foot 12

19 The inner side of the second carrier foot 13

20 side cheeks of the first carrier foot 12

21 Side cheeks of the second carrier foot 13

22 The central area of the first carrier foot 12

23 The central area of the second carrier foot 13

24 grooves

25 the outer side of the first carrier foot 12

26 Outer side of carrier base 14

27 The outer side of the second carrier foot 13

28 first recess

29 Second recess

30 cable channels

31 Another cable channel

32 end section of common cable 11

33 The emission hole in the first recess 28

34 Receiving hole in the second recess 29

35 Acceptance Profile for Carrier Part 2

36 The first elastic zone

37 Second elastic zone

38 area

39 support section

39a First support segment

39b second support section

39c The third support section

40 The transition part between the second elastic leg 16 and the elastic base 17

41 steps

42 The end section of the first elastic leg 15

43 The initial section of the first elastic leg 15

44 straight section

45 stop part

46 slope section

47 concave segment

48 fixing strap

Claims (14)

1. A medical sensor for measuring pulse, blood, tissue and/or skin parameters using electromagnetic waves in a transmission method, - comprising a clip-like carrier part (2) for being pushed on the patient's finger or toe, - wherein the first carrier foot (12) of the carrier part (2) carries at least one emitting element and rests on the finger or toe with the inner side (18) of the first carrier foot during the measuring operation, - the second carrier foot (13) of the carrier part (2) carries at least one receiving element and passes through the inner side ( 19) while resting on the fingers or toes, - the carrier base (14) of the carrier part (2) connects the first and second carrier legs (12, 13) to each other in the region of the fingertips or toes, - providing a clip-like elastic part (3) having first and second elastic legs (15, 16) and an elastic base (17) connecting said first and second elastic legs (15, 16), - the elastic part (3) is arranged on the outer side of the carrier part (2), so that the first elastic foot (15) rests on the outer side (25) of the first carrier foot (12), And the second elastic leg (16) abuts against the outer side (27) of the second carrier leg (13), - said carrier part (2) is made of a more flexible material than said elastic part (3), - said first and second elastic feet (15, 16) prestress said first and second carrier feet (12, 13) towards each other. 2. The sensor according to claim 1, characterized in that, - said carrier part (2) is made in one piece, and/or - The elastic portion (3) is made in one piece. 3. The sensor according to claim 1 or 2, characterized in that, - said elastic portion (3) has at least one elastic zone (36, 37) connecting together two support segments (39) adjacent to said at least one elastic zone, - The stiffness of the support section (39) is better than that of the elastic zone (36, 37). 4. The sensor according to claim 3, characterized in that, the elastic regions (36, 37) of the elastic part (3) are at least two elastic regions (36, 37) with different elastic characteristics, the at least The two elastic zones include a first elastic zone (36) and a second elastic zone (37). 5. The sensor according to claim 4, characterized in that the support section (39a, 39b) adjacent to the more flexible elastic region (36) is formed with a stop part (45), which Bending deformations in this elastic zone (36) are limited to a predetermined extent during the expansion of the carrier legs (12, 13). 6. The sensor according to claim 4, characterized in that, - said first elastic zone (36) is formed at the transition (40) between said second elastic foot (16) and elastic base (17), and/or - said second elastic zone (37) is formed in the middle of said elastic base (17). 7. The sensor according to claim 4, characterized in that, - said first elastic zone (36) is formed at the transition (40) between said second elastic foot (16) and the elastic base (17), - a second elastic zone (37) is formed in the middle of said elastic base (17), - The stiffness of the second elastic zone (37) is better than that of the first elastic zone (36). 8. The sensor of claim 1, wherein - the carrier base (14) is designed as a concave section (47) into which fingernails or toenails protruding beyond the tip of the fingernail or toenail can protrude during the measuring operation middle. 9. The sensor of claim 1, wherein - said inner sides (18, 19) of said first and second carrier legs (12, 13) are curved in a concave manner in a direction transverse to the push-on direction, - on each of said carrier feet (12, 13), side cheeks (20, 21) from the central region (22, 23) of said first and second carrier feet (12, 13) towards the respective opposite The sides of said first and second carrier feet (12, 13) protrude outwards, - said elastic portion (3) prestresses said first and second carrier feet (12, 13) towards each other, so that before pushing said sensor (1) on a finger or toe, the The carrier feet (12, 13) abut against each other at their side cheeks (20, 21). 10. The sensor according to claim 1, characterized in that a groove (24) is provided on the outside of the carrier part (2), and the groove extends from the outside of the first carrier leg (12) ( 25) extending through the outer side (26) of the carrier base (14) to the outer side (27) of the second carrier foot (13), in which the at least one transmitting element and the at least one receiving element are arranged, and Connecting cables (7, 8) for the transmitting and receiving elements are placed therein, wherein the elastic part (3) closes the recess (24) from the outside. 11. The sensor according to claim 1, characterized in that the carrier part (3) has fastening means which allow the sensor (1) to be put on after the sensor (1) has been pushed on a finger or toe ) fixed on the fingers or toes. 12. The sensor of claim 11 wherein, - said first elastic foot (15) has an initial section (43) adjacent to said elastic base (17), and an end section (42) remote from said elastic base (17), - said end section (42) is more flexible than said start section (43). 13. Sensor according to claim 12, characterized in that the end section (42) is stiffer than the second elastic region (37). 14. The sensor according to claim 12 or 13, characterized in that said end section (42) is connected to said start section ( 43) Connected.

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